Three dimensional sensing element suspension method and measurement system

Abstract

Methods of determining movement and devices that can be configured to function as an accelerometer, a gyroscope or a magnetometer and is comprised of a sensing element suspended by acoustic waves, and a measurement system capable of determining the position, or rotation of the sensing element without introducing any residual force on the sensing element. The acoustic suspension of the sensing element provides a virtually friction, and torque free method of constraining the sensing element, but not hindering its ability to sense accelerations, rotations or magnetic fields.

What is claimed is: 
     
       1. A system for determining movement, comprising:
 a sensor comprising:
 a housing having a space within the housing; 
 an object having a magnetic property along an axis of the object forming a magnetic orientation of the object, the object positioned within the space in the housing; 
 
 a plurality of ultrasound transmitters arranged around the space such that the object is in-between at least a portion of the plurality of ultrasound transmitters, the plurality of ultrasound transmitters configured to collectively generate ultrasonic sound waves that strike the object, the ultrasonic sound waves causing the object to be suspended in the space between the plurality of ultrasound transmitters, with the axis aligned in a position relative to a magnetic field; and 
 one or more detectors configured to produce signals corresponding to the movement of the object in the space. 
 
     
     
       2. The system of  claim 1 , further comprising a controller that receives the movement signals from the one or more detectors and determines movement information of the sensor in at least one dimension. 
     
     
       3. The system of  claim 2 , wherein the system operates as a magnetometer. 
     
     
       4. The system of  claim 2 , wherein the controller receives the movement signals and determine movement information of the sensor in two or more dimensions. 
     
     
       5. The system of  claim 1 , wherein the object comprises a spherical body. 
     
     
       6. The system of  claim 1 , wherein the object comprises an aperture on the axis, and the object further comprising magnetic material positioned in the aperture. 
     
     
       7. The system of  claim 1 , wherein the one or more detectors detection mechanism comprise at least one camera. 
     
     
       8. The system of  claim 7 , wherein the object comprises one or more alignment marks, and the at least one camera is configured to image the one or more alignment marks. 
     
     
       9. The system of  claim 1 , wherein the one or more detectors comprise at least one laser tracking system comprising at least one laser light transmitter and one laser light receiver. 
     
     
       10. The system of  claim 1 , wherein the plurality of ultrasound transmitters comprises four or more ultrasound transmitters. 
     
     
       11. The system of  claim 1 , wherein the plurality of ultrasound transmitters are arranged to produce ultrasound waves aligned in at least three different directions. 
     
     
       12. The system of  claim 1 , further comprising a fluid in the space within the housing, the object being suspended in the fluid. 
     
     
       13. The system of  claim 12 , wherein the fluid is a gas. 
     
     
       14. The system of  claim 12 , wherein the fluid is a liquid. 
     
     
       15. The system of  claim 1 , further comprising one or more excitation coils configured to cancel the effect of an existing magnetic field on the object. 
     
     
       16. A method, comprising:
 providing a sensor comprising:
 a housing having a space within the housing, 
 a plurality of ultrasound transmitters arranged around the space such that an object positioned in the space is in-between at least a portion of the plurality of ultrasound transmitters, and 
 one or more detectors; 
 
 positioning the object in the space in-between at least a portion of the plurality of ultrasound transmitters, wherein the object is magnetized along an axis, and the axis is aligned relative to a magnetic field when the object is positioned in the space; 
 providing acoustic energy from the plurality of ultrasound transmitters incident on the object, the acoustic energy suspending the object in-between at least a portion of the plurality of ultrasound transmitters; 
 generating signals from the one or more detectors based on movement of the object; and 
 determining, by a controller, movement of the sensor in at least one dimension based on the signals received from the one or more detectors. 
 
     
     
       17. The method of  claim 16 , wherein the housing comprises a liquid in the space within the housing, the object being suspended in the liquid. 
     
     
       18. A system for determining movement, comprising:
 a sensor comprising:
 a housing having a fluid in a space within the housing, 
 an object positioned within the space in the fluid, the object being magnetized along an axis, 
 a plurality of ultrasound transmitters arranged around the space such that the object is in-between at least a portion of the plurality of ultrasound transmitters, the plurality of ultrasound transmitters configured to collectively generate ultrasonic sound waves that strike the object, the plurality of ultrasound transmitters arranged to produce ultrasonic sound waves aligned in at least three different directions; 
 one or more detectors positioned to generate signals based on the movement of the object within the space; 
 
 a controller that receives the movement signals from the one or more detectors and determines movement information of the sensor in at least one dimension. 
 
     
     
       19. The system of  claim 18 , wherein the fluid is a liquid. 
     
     
       20. The system of  claim 18 , wherein the plurality of ultrasound transmitters comprises at least four ultrasound transmitters.